‘God’s own country’; Kerala has a continuous chain of streams, water bodies, creaks, lagoons and backwaters along its coastal region. These water bodies are fed by rivers and drain into the Lakshadweep Sea through small openings in the sandbars vernacularly called ‘azhi’, if permanent or ‘pozhi’, if temporary is a wonderful creation of nature blessed in this part of the world.
The Vembanad wetland system and its associated drainage basins are unique in terms of physiographic, geology, climate, hydrology, land use, ecology and with its marvelous diversity of flora and fauna. The rivers are generally short, steep and fast flowing due to the intricate topography and its vertical terrains. Rivers and connected water bodies in Kerala are dynamic annually by monsoon and the water received is holding at montane grass and forest ecosystem. The Vembanad wetland system includes the Vembanad backwater, the deltaic lower reaches of the rivers draining network and the adjoining Kol wetlands.
Vembanad Topography
The Vembanad wetland system and its associated drainage basins lie in the humid tropical region between 09˚00’ -10˚40’N and 76˚00’-77˚30’E. The Lake is bordered by Alappuzha (Alleppey), Kottayam and Ernakulam districts of Kerala covering an area of about 200 sq km and extending 80 km in a NW-SE direction from Munambam in the north to Alleppey in the south. The width of the lake varies from 500 m to 4 km and the depth from <1m to 12m. Manimala, Meenachil, Pamba and Achenkovil flow into the lake south of Thanneermukkom and Muvattupuzha river flows into the Cochin backwaters north of Thanneermukkom barrage. The lake has got a freshwater dominant southern zone and a salt water dominant northern zone, both separated by a bund at Thanneermukkom, where the lake has its minimum width. The bund was constructed in 1975 to prevent salt water intrusion and to promote double cropping of paddy in about
55,000 ha of low lying fields in the area (Padasekharams). To check the floods during monsoons, a slipway was constructed at Thottappally in 1955, for speedy drainage of water from the lake to the Arabian Sea. In the south where the lake attains its maximum width, the eastern half has been reclaimed for irrigation purposes and bunds have been constructed.
History and myth
Vembanad is having a glorious past which has been evolved through both history and myth. The lake has taken its name from the ancient kingdom of Vempolinad which split itself into the principalities of Vadakkumkur and Thekkumkur. The holy river Pampa was flowing through Vempolinad. As a result of geographical changes, Vempolinad was sunk to the interior part of the earth. Along with this a portion of the river Pampa was also sunk with Vembanad. The Vembanad Lake is formed out of these geological changes. Beneath the lake, there is a portion which people call it as ‘kappal chal’ and this has been considered as a continuation of Pampa.
I) Biodiversity status
Vembanad Ramsar site
Based on the rich biodiversity and socio economic importance, Vembanad along with adjacent Kol- lands was declared as a Ramsar site, a wetland of international importance (Ramsar Convention, 2002). Vembanad Kol wetland and its ten associated drainage basins are characterized by continuous chain of back waters.
Unique Biodiversity
This wetland supports rich diversity of water birds, fishes, aquatic plants and other life forms. Lake supports a population of more than 20,000 water fowls in India during the winter months. The lake helps to contain flood waters and saves thickly populated areas from submersion, recharges coastal aquifers, filters and
flushes out pollutants, facilitates inland navigation and wetland tourism. The system supports unique cultural traditions, water centered social institutions and life styles. Acting as a carbon bomb, this wetland can play a significant role in reducing the dreadful impacts of climate change.